Cooler for cement clinker



prl 22, 1941, R. D. PIKE TAL 2,239,246

COOLER FO QEMENT CLINKER Filed Aug. l5, 1938 4 Sheets-Sheet l ,f/ ,cf/3', @Hx if, E INVENTORS.

@645W ATToRNEK R. D. PIKE E-r AL COOLER FOR CEMENT CLINKER Filed Aug. l5, 1938 4 Sheets-Sheet 2 M Eb.;

ATTORNEY.'

R. D. PIKE Er/AL' COOLER FOR CEMENT CLINKER Filed Aug. 15, 1958 4 .SheetsP-Sheet 3 Y INVENTORS. ma@ i). ma,

au@ wtcl. @a WMM A TT ORNE Y.

April 22, 1941. R. D. PIKE .ET A1,v l 2,239,246

COOLER FOR CEMENT CLINKER INVENTORY. 8 .7i/e,

A TTORNEY.

Patented Apr. 22, 1941 Nr France 2,239,246 COOLER FOR CEMENT CLI'NKER Robert D. Pike,Piedmont, and 'Dudley Baird, Berkeley, Galif.

ApplicationAug-ust 15, 1938, Serial No. 224,956

7 Claims.

The present invention relates to Aclinlrer coolers of vthe general ,typedisclosed in our Patent Number'1,`529,808 for Regenerative clinker cooler, issued March `1'7, 1925.

It is the function of .a clinker coolerfof this type to receive clinker rfrom a cement clinker burning kiln at a temperature of about 2500 Fahrenheit .or greater, and cool it to about200 Fahrenheit, at which vtemperature it kmay be ground to form cement. Rapid. cooling is to be desired in nthat quickly cooled clinker is more easily ground and produces a .better qualityof cement rthan :that .which is cooled slowly. As large quantities of sensible heat are present .in the clinker Whichis delivered to the cooler, it is desired to .preserveas much of this sensible heat as possible :by 'transferring it from the clinker to the air .used for cooling it and to utilize this heated air for combustion lof fuel in the kiln.

The apparatus described in thepatent referred to above is 'of the kind comprising `a verticalcylinder containing upper and `lower hearths, over which rabble .arms move to .rabble the .clinker which is Adepositedupon the hearths, and expose it to a current rof cool air conducted through these arms.

The present invention ypertains toa `cooler of this same general type, and it is theobject of n the invention to provide insucha cooler means for effecting a highly eicient vtransfer lof :heat between the clinker and theair used in cooling it.

A further object is to attain a coolingof clinker by means of directingair onto the clinker in such relation to the travel of rabble teeth therethrough that heat transfer will voccur Vat a rapid rate.

It is a further object of the invention to provide auxiliary cooling means for directing a flow of air upwardly through the clinker Lwhile it is being rabbled to supplement the `cooling -`effect of the air passing through the rabble arms.

A still further object-is'cthe provision of `means Afor directinghot kair romthe cooler to the kiln so as to conserve the heat of saidzair and to provide means for sensitive regulation of theamount of Vair directed tothe kiln, such means also operating to insure that the hottest air from .the cooler is directed to the kiln.

Other objects and advantages of the invention which tend toward general eiiiciency. in operation and `toward'accomplishment of the requirements dened above will be made apparent Lin the following .speciication wherein 4reference ais made to the accompanying drawings.

Fig. lis a vertical, Vsectional view vof a clinker cooler embodying our invention.

Fig. 2 is a fragmentary section taken on line II-II of Fig. v1.

.Fig.3 is an enlarged View in elevation of aportion of a rabble arm, illustrating detailsfof ithe rabble teeth and air :nozzles carried by thearm.

LFig. '.4 .is a sectional view, taken online V-IV of Fig. 3.

Fig.t.5 isa plan View oa-,portionoftherabble arm shown in Fig. 3.

Fig. 6 is a perspective view otagrate section which forms a portion of the lower hearthof the cooler.

.Fig. 7 is a vertical, transverse, sectionalview of threegrate sections such as vthatshown .in Fig'. 6, ,illustrating .their relative position when assembled.

Fig. 8 is aplan view ci kthree such .gratelsections 1in .assembled relation.

Fig.'9 Vis v'a diagrammatic view in plan of the clinker `cooler illustrating the arrangement of exhaust ventsand 'fan associated therewith.

.Referring particularly to Figs. 1 and'2 of the drawings, the present invention is illustratedas embodied in V4a vertically disposed rtWo-heartlfi clinker cooler. The lower'hearth of the cooler is generallyindicated at I0 and is surrounded by a wall Il, which wall supports .an upper hearth l2 and a roof I3. The vmain structureis, .as illustratecl,` of vrefractory material suitably supported and braced by steel plate and structural `forms.

A rotatable vertically extending column |15 `is disposed ,concentrically of the cylindrical cooler and is .supported at its lower end by a bearing I6 for rotation through. suitable gears i1 and i8 by drive means :herein illustrated as a motor t9; The column l5 isprovided Withan air sealwhere itpasses through thelower vhearthl inthe form of a lutezring 2U and Alute Vcap :2l Awhi'ch,under operating conditions, will be embedded in clinker that is being cooled.

4An air seal;is.provided .w-herethe column Vpasses through the roof .1,3 by .means otalu-te cap`2-2 cooperating with a sandsealring 23,.'into `which the-downwardly extending flange'of thelute ring 22 extends. yThe uppermost end of ,the column l5 is guided inra bearing 2d and is connected through a suitable packing Vjoint, generally indcated` at 25, with the Aend ol 1a stationary :air ductl which communicates with a source offair under pressurernot shown, but which may, in accordance Awith custom, be in the form of tax-fan or blower.

Hollow rabble arms 35 communicate with the interior of the column I5 through ports 3| and are supported thereby to extend radially outwardly to overlie the upper hearth I2 and the lower hearth I il. The rabble arms support rabble teeth 3| which, upon rotation of the column I5, pass through the beds of clinker disposed upon the hearths I5 and I2, and the arms also carry nozzles, indicated at 32, communicating with the interior of the arms and thus with the interior of the column and the source of supply of air, so that as the column I5 is rotated, the clinker is rabbled by the teeth 3I and cooled by air directed onto it through the nozzles 32. The construction and arrangement of the rabble teeth and the nozzles will be described in detail hereinafter.

A clinker drop 34 receives hot clinker from a kiln (not shown) for introduction to the cooler,

and clinker falling through the drop 34 deposits on a shelf 35 from which it may slide or fall into the interior of the cooler and on to the upper hearth I 2. An air duct 35, below the shelf 35, communicates with the source of air under pressure by a conduit (not shown) and supplies air to a narrow horizontally extending slit 3l entering through the wall of the cooler and serving the purpose of blowing or fanning the clinker falling from the shelf 35 onto the upper hearth I2, so that an initial cooling of the hot clinker is obtained and so that it is caused to be spread over the surface of the hearth I2 in the path of the rabble teeth passing thereover.

The rabble teeth on the arms 3l), which overlie the upper hearth, are disposed at an angle to plow or agitate the clinker and gradually move itinwardly of the hearth as it is subjected to the cool air directed against it through the medium of the nozzles 32. The upper hearth I2 is provided with aA central opening 40, through which the column I5 passes, and this opening 40 is considerably larger in diameter than the column so that as the clinker falls through the opening 4D it isdeposited on the lower hearth adjacent to the inner ends of the lower rabble arms and in the path of the rabble teeth passing over the lower hearth, these teeth being disposd at an angle to cause gradual movement of the clinker outwardly until it reaches the outer periphery of the lower hearth.

A discharge chute 42 is provided at a point ad- `acent to the outer periphery of the lower hearth I, and the cooled clinker falls through this chute onto a sealing trap door 43, hinged, as at 44, and counterbalanced by a weight 45. The construction of this seal is such that the cooled clinker is discharged therefrom at intervals when its weight on the door. overcomes that of the balance weight 45. As it is discharged from the chute 42, the clinker is deposited on a conveyor belt 46 by means of which it is carried to a suitable grinding apparatus.

The construction and position of the rabble teeth 3I are best illustrated in Figs. 3, 4 and 5, in which the teeth 3l are shown as vertically disposed plates depending from horizontal plates 50, each of which is providedwith a circular undercut head 5I, slidably and rotatably fitting within a groove 52 formed in the lower surface of the rabble arm 30. This mounting of the plates permits them to be adjusted to any desired angle, and they may be locked or secured in their adjusted positions by mechanism commonly used for this purpose, which mechanism forms no part of the present invention, and is, therefore, not disclosed herein.

The angularity of the rabble teeth 3| on the rabble arms which overlie the hearth I2 is such that the clinker on said hearth will be rst distributed around the outer periphery of the hearth and will then be advanced inwardly as it is rabbled to fall upon the lower hearth I 0 near its center. The teeth on the lower rabble arms are disposed at an opposite angle to cause the rabbled clinker to be moved outwardly, with the exception of four or live of the outermost teeth on alternate arms overlying the lower hearth, which teeth are disposed at an angle opposite to the other teeth, as illustrated in Figs. 1 and 2, to retard the outward movement of the clinker and to control its depth during the nal rabbling process, and at a time when additional cooling air is supplied through an annular grating, generally indicated at 55 in Fig. 2.

As shown in Figs. 3, 4, and 5, each nozzle 32 comprises an L-shaped tting, one end of which is adjustably tted in a port 56 in the side wall of the rabble arm 30, and the other end of which extends in a generally downward direction. The ports 56 may be arranged in opposed pairs so that through-bolts 5'I serve each to retain two nozzles in place, or, if desired to obtain a required distribution of air, the nozzles on opposite sides of the arm may be staggered, each being held by a separate'bolt similar to the bolts 51.

In practice, it has been found desirable to adjust the angularity of the nozzles lso that one directs a stream of air on the leading side of the rabble arm vertically downwardly upon the clinker, while the corresponding nozzle on the trailing side of the arm is adjusted at an angle to cause the air owing through it to impinge partly upon the rabble teeth and partly upon the clinker as it is agitated or stirred by the teeth. It should be understood, however, that the adjustment of the nozzles may be varied depending upon the position of the teeth and depending'upon other operating conditions, so that the air flowing through the nozzles will be used to best advantage for the purpose of cooling clinker and for the additional purpose of maintaining the rabble teeth at a reasonably low temperature.

As a greater supply of cool air is necessary to effect the iinal cooling of the clinker than is necessary during the initial cooling process, the present invention contemplates supplementing the air which is supplied through the rabble arms with a supply of fresh ycool air introduced upwardly toward the outer periphery of the bottom hearth ID through the medium of the grate 55, the details of construction of which are illustrated in Figs. 6, 7 and 8. This grate is made up of radially extending sectionss, as illustrated in Fig. 6, each of which comprises a grate bar 63, provided with an opening 6I at one edge, underlying which opening is an integrally formed louver 62. The louver 62 extends beyond the edge of the bar to underlie the edge of the adjacent bar, as illustrated in section in Fig. 7, thus to permit upward passage of air but to prevent clinkeroverlying the grate from escaping downwardly therethrough.

An annular air conduit 'I3- (see Fig. 1) underlies the grate 55, and cool air, under pressure, is supplied to said-conduit to be directed upwardly through the grate andthrough the clinker overlying the grateby means'of ducts 'II (see Figs.

l and 2) opening into the annular conduit "'19 through 'ports '12.

A hotlair exhaust'flue -1.3, opening through the roof of the clinker cooler, ser-vesto-exhaust the heated Vair therefrom and'direc't it to the` kiln where it is utilizedas air v'for combustion. The amount of air used in cooling the clinker, and particularly where additional air is blown through the grate '.55as described above, is greatly in excess of the air required in the kiln. In order, therefore, to provide means for accurately regulating the volume of exhaust air directed to the kiln, and in order to insure that this exhaust air is the hottest air which leaves the clinker cooler, exhaust vents 14 are provided in the side wall of the cooler in communication with the lower hearth chamber. A variable speed suction fan is connected with the vents 14 to withdraw from the cooler all air that is not required in the kiln. In Fig. 9 wherein the clinker cooler is shown diagrammatically in plan view, the vents 14 are shown as communicating with conduits 80 and 8l which join and enter the intake end of a suction fan 82. A motor 83 which drives this fan is energized by a circuit 84 in which is included a variable resistance 85 to vary the speed of the motor and consequently the speed of operation of the fan. This variable speed suction fan, which may be of any standard construction, serves as means for accurately regulating the volume of air passing through the exhaust flue 13, and by reason of the fact that it communicates with the outer zone of the lower chamber rather than with the upper chamber, it draws off the cooler air rather than the air which comes in contact with the hottest clinker being rabbled on the upper hearth. The air withdrawn through the vents 14 is naturally laden with dust and may be cleaned in a conventiona1 cyclone and the dust returned to the belt 46.

Suitable doors for inspection and repairs are arranged, as illustrated at 16, in the wall of the cooler in a position to permit removal of the rabble arms 30 for repair and replacements thereon.

In practice, the very hot clinker which enters the cooler is first subjected to the cool air entering through the slit 31 below the clinker drop and then to the air flowing through the upper rabble arms and directed by the nozzles 32 of said arms against the upper hearth. By the time the clinker falls to the lower hearth, it has given up more than half of its heat to the air which has impinged upon it from the slit 31 and from the nozzles 32 of the upper rabble arms. That is, it has been reduced from a temperature of about 2500 Fahrenheit to a temperature of about 1200 Fahrenheit. When it falls upon the lower hearth, it is further cooled by air owing through the nozzles associated with the lower rabble arms, and at the time that it reaches the inner edge of the grate, it has been reduced to a temperature of approximately 600 to 800 Fahrenheit. The air which has impinged upon the clinker up to this point is substantially that air which passes upwardly and is utilized for combustion in the kiln.

As the partially cooled clinker is moved over the grate, it is acted upon by air from the four or ve pairs of nozzles on the outer ends of the lower rabble arms and also by the air which is blown up through the grate. These two quantities of cool air taken together will in every case be suflicient to cool the clinker to its final tem- ,Parature ready for discharge from the cooler, 75

which 'is vusuallynot more than 140 lFahrenheit above atmospheric temperature, :but mayxvary slightly .from thisin accordance with the quantity of air introduced through the grate .and the outer-nozzles aforesaid. The temperature of the air which Apasses 'through the nozzles ofthe .lower farms and through the grate after it y'has impinged upon and has ,passed through the clinker is relativelyllowbecause the clinker itself is relatively cool. Ordinarily the temperature of this air will range from 200 Fahrenheit to 250 Fahrenheit. This is the air which is withdrawn through the ports 14, and although there is no means forming a mechanical division between this air and the air which passes upwardly to the kiln, the natural tendency of cold air to remain in the lower part of the cooler will result in the coolest part of the air always passing out through the ports 14. Furthermore, by varying the speed of the suction blower, a sensitive regulation of the amount of hot air flowing to the kiln is obtained at the same time, preventing any unnecessary intermingling of the air from the upper hearth chamber with the air in the lower hearth chamber. This method of regulating the flow of air through the exhaust ue 13 to the kiln also tends to effect a slight negative draft throughout the cooler, thus preventing undesirable blowing out or expelling of hot air and dust.

What we claim is:

1. A clinker cooler comprising vertically spaced hearths, rabble arms rotating over said hearths, means for directing cooling air through said rabble arms onto the clinker on said hearths, a grate at the outer periphery of the lower hearth, and means for directing air upwardly through said grate and through the clinker overlying the grate.

2. A clinker cooler comprising upper and lower hearths, means for delivering hot clinker to the upper hearth and for advancing it inwardly thereover, said upper hearth having a central opening through which the clinker falls to the lower hearth, means for advancing the clinker outwardly over the lower hearth, an air admitting grate surrounding the lower hearth, and means for retarding the outward movement of the clinker overlying said grate.

3. In a clinker cooler having vertically spaced hearths and rabble arms for rabbling clinker disposed on said hearths, adjustable teeth carried by said arms, and a plurality of nozzles adjustably supported by said arms for directing air against the teeth and the clinker.

4. In a clinker cooler of the character described, a hollow rabble arm having rabble teeth depending therefrom to engage with and rabble clinker to be cooled upon movement of the arm, a pair of nozzles for each tooth adjustably supported from opposite sides of the arm adjacent to the tooth, and means for passing cooling air through the arm and said nozzles to impinge on the rabble teeth and the clinker.

5. In a multiple hearth clinker cooler, a rotating central column with an air passage, rabble arms attached thereto with connecting air passages, rabble teeth on said arms, means for directing air jets downwardly from the arms upon the clinker in the vicinity of said teeth, and an annular grate on the outer perimeter of the lowermost hearth for forcing air upwardly through the clinker.

6. In a multiple hearth clinker cooler, a rotating central column with an air passage, rabble arms attached thereto with connecting air pas- "7. `In a cooler for clinker or the like a hollow rabble arm, rabble teeth depending therefrom, air nozzles communicating with the interior of the arm to disperse air forced through the arm, {and means to adjust the direction of said nozzles to vary the quantity of air impinging on the teeth.

ROBERT D. PIKE.

DUDLEY BAIRD. 

